Mass spectrometry has become an essential technique for the analysis of biological macromolecules such as proteins and nucleic acids. Ionization techniques for involatile materials are key to the success of mass spectrometry in biology and medicine. Matrix assisted laser desorption/ionization (MALDI) is one such method. Further development of this technique will be dependent upon the identification of new matrix materials with properties of a type that have not been exploited before now. We propose to investigate the use of explosives as new matrices that will impart additional energy to the analyte upon laser irradiation, thereby increasing the sensitivity of detection. This will require the systematic study of the interactions between potential matrices and biopolymers. The UCSF Mass Spectrometry Facility will provide access to MALDI instruments for these studies and will thereby be critical to the successful outcome.